I once had a friend whose AC compressor stopped functioning. Upon testing he determined there was no control voltage going to the clutch coil. Traced it back to the PCM. Upon opening the PCM he found burnt traces and a blown component. With the face of the component missing the best we could do was guess at what that transistor like device was. Stealing stock from the company we installed an NPN transistor in that position and repaired the traces. Upon reinstalling the PCM into the vehicle the AC compressor was then engaging. Cost of less than a penny - as the company bought in bulk - the AC was fixed. I never heard if the repair continued to hold, so that part I can't guess at. It's not like we knew what we were doing it was just a shot in the dark that managed to hit the target.

I get it. Allowing PCM's to be repaired could put the automotive company in liability jeopardy if something goes wrong and an injury or death occurs. Some businesses order boards from board houses and if a solder joint has to be reworked more than 3 times to comply with standards the company is instructed to just scrap the board as they don't want something that its reliability has been compromised.

Aside from proprietary concerns, sharing schematics can harm their bottom line. So they don't share.

 

Additionally, plastic semiconductor packages are not hermetic. Not by a wide margin. The moisture may have already creeped inside and damaged the die itself.

 

If that one part was that severely corroded, what else in that "PCM" package is/was corroded?? If you can see the actual traces, you should be able to see what the connections to that device were. Then you can possibly guess the pin-out.
QUESTION: what was not working that you investigated??If one of those leads goes to a connector pin, what was that?? AND it might be that the center pin was a 12 volt feed. So a bit more tracing can probably give a lot more insight.
OR has the whole F250 quite running because of this failure??

With the vehicle being a 1997 F250, there should be a few of them in a salvage yard, or even in a wreckers yard. And certainly a module would be rescued before crushing the body. So finding a used module may also be an option.

AND, really, if there was that much corrosion that you could repair, how much more is hidden???

 

If that one part was that severely corroded, what else in that "PCM" package is/was corroded?? If you can see the actual traces, you should be able to see what the connections to that device were. Then you can possibly guess the pin-out.
QUESTION: what was not working that you investigated??If one of those leads goes to a connector pin, what was that?? AND it might be that the center pin was a 12 volt feed. So a bit more tracing can probably give a lot more insight.
OR has the whole F250 quite running because of this failure??

With the vehicle being a 1997 F250, there should be a few of them in a salvage yard, or even in a wreckers yard. And certainly a module would be rescued before crushing the body. So finding a used module may also be an option.

AND, really, if there was that much corrosion that you could repair, how much more is hidden???

No the truck was still running the issue is that the PCM stop telling the regulator to turn on the charge the batteries but kick the e brake plate then it and get voltage back and charging batteries again and notice that it was not very steady so I open the PCM up fix corrosion and the other compressors and this is the last part of the puzzle